The Xiamen Symposium on Marine Environmental Sciences (XMAS 2027)

The Transpolar Drift (TPD) is a critical conduit for exporting freshwater, sea ice, and biogenic material from the Pacific Arctic to the North Atlantic, playing a vital role in the Arctic’s energy budget and global climate system. However, limited coverage of satellite altimetry over the central Arctic has long hindered a complete understanding of the TPD’s full variability. In this study, we use a new, gap-free Dynamic Ocean Topography (DOT) dataset spanning from 2011 to 2025 – which covers the previous data void over the North Pole – to investigate the interannual variability of the TPD pathway. By analyzing DOT-derived surface geostrophic velocities and defining an “eastward extension index” to quantify TPD pathway shifts, we find a pronounced reorientation of the main portion of the TPD after 2020. Specifically, more of the TPD exits through Fram Strait rather than the Canadian Arctic Archipelago, indicating a recent reorganization of Arctic outflow pathways toward the Atlantic sector. This pathway shift is verified by Lagrangian particle tracking experiments and appears linked to concurrent shifts in large-scale atmospheric forcing. Our findings provide observational evidence that the TPD’s transport capacity has recently entered a new regime, with profound implications for the redistribution of freshwater, the fate of sea ice, and the delivery of nutrients and pollutants across the Arctic Ocean.